Transmission for power lawn mowers



March 8, 1949. CARLSON 2,464,175

TRANSMISSION FOR POWER LAWN MOWERS Filed Nov. 10, 1944 2 Sheets-Sheet l INVENTOR. J A.Epw/N CARI-SON FIG. 2

ATTORNEY March 8, 1949. J. A. E. CARLSON TRANSMISSION FOR POWER LAWN MOWERS 2 Sheets-Sheet 2 Filed Nov. 10, 1944 H 4 v INVENTOR.

J, A. EDWIN CARLSON ATTORNEY Patented Mar. 8, 1949 TRANSMISSIDN FUR POWER LAWN MGWVERS J. A. Edwin Carlson, Racine, V/is, assignor to Jacobsen Manufacturing Company,

Racine,

Wis., a company of Wisconsin Application November 10, 1944, Serial No. 562,842

4 Claims.

The present invention relates to a belt transmission which is particularly adapted for on power driven lawn mowers and the ilk having means associated therewith whi swers the purpose of a clutch, operable b mote control preferably by means of 2. Bo wire.

For power lawn mowers, particularly ti guided type, which are driven by str l combustion engines which not onl, power for driving the blade carrying but also the motive power for the ground wi" wherein the operator has nothing to do to guide and start and stop the device, an cants invention is particularly suited.

For devices of the class, I provi .e the simplest form and easiest to operate transmission, l viding a V belt drive wherein the p" relatively close together and where and stopping is accomplished by 131 5.0. n. loosening the belt.

In applicants device, starting and sto accomplished by the use of far less ene when a clutch is used. The first cost is far less and adjusting is simpler and easier to accomplish than with a clutch system.

To these and other useful ends, my consists of parts, combinations of equivalents, and mode of operation as her after described and claimed and shown in accompanying drawings in which:

Fig. 1 is a fractional top view of my improved device as applied to lawn mowers.

Fig. 2 is a rear View of the device srnilar to that shown in Figure 1, and as attached to the mower frame plate.

Fig. 3 is a left hand end view of the device.

Fig. 4 is a view of the device taken from line 44 of Figure 1.

As thus illustrated, the device is adapted to form an operating connection between the engine crank shaft and a secondary or drive In the drawings, the engine crank shaft is designated by reference character F3, to which a V belt driving pulley H is attached. The sec-- ondary shaft 12 is rotatably mounted on a mower base plate It as follows:

Spaced brackets i l-l are secured to plate l3 as clearly illustrated in the figures. A shaft 55 is slidably mounted in the upwardly extending portions of members M and held in working position by means of cotter pins as lil5. A tube I! is rigidly secured at its right end to a post I 8 as at I9, the left end of the tube being rigidly secured to a post as at it. Posts 58 (C1. Yd-242.16)

and 2d are pivoted at their lower ends to shaft 15 as at 2| and 22. Thus it will be seen that tube ll may be moved forwardly and rearwardly on shaft It as an axis.

Shaft I2 is rotatably mounted in tube il as clearly illustrated in Figure 2, having a V belt pulley 25 secured to its left hand end. A V belt 25 forms an operating connection between pulleys H and 25 and when shaft is in the position. shown, this belt is loose enough to slip for idling speed of the engine.

The means for tightening the belt for operat ing the mower consists of a bracket whic suitably secured to the engine. A lever as is pivotally mounted on tube il having a suitable means as at 28 at its bottom to which preferably a Bowden wire 35E) may be secured, this connection being pivotally mounted in openings 31.

On the rear end of member l'l I turnably mount a member 32, the head of which provided with a screw-driver slot Member is provided with a pintle 3% which is considerably offset as shown in Figure l, and extending through an opening 35 in member 2?. This pintfe is suoplied with a lock washer and nut so 532 can be turned and locked in any desired position. Member 32 carries a roller and lei r 28 is shaped as shown in Figure i so that wh n the front surface at 38 lays on the roller menu ber 52 will be adjusted to a position w h will permit the belt to slip freely for free idling of the engine.

A cam surface 33 terminates into a slight depression and continues so as to form a raised surface ll, the shape of the surfaces 46 and 4! being similar to the outside diameter of roller 3'8. It will be noted that the engine base, designated by reference character i is mounted on base plate it and that member 2? is therefore held rigid relative to base plate l3.

Thus when the operator pulls rearwardly on Bowden wire 33 cam surface 30 will cause tube I! to move rearwarclly on shaft l5 as an axis and t1 ten the belt enough to drive the mower. The S1l.;-;.-.113 depression at M! will prevent the clutch from being accidentally disengaged and the surface will limit the travel of lever 28; thus engaging and disengaging the clutch or belt will be brought about by pulling and pushing on the Bowden wire 30.

It so happens that a V belt slips readily and with ver little friction when slightly loose and that very little tension will cause the belt to grip the pulley for maximum power transmission. The design of my device prompts the operator to 3 adjust the belt so it will be only tight enough to transmit maximum power and when it is noticed by the operator that the belt is not tight enough it is a simple matter to loosen and turn member 32 on its eccentric pintle 34.

In hand guided power driven mowers it is the custom to chain drive the blade carrying rotator and drive the ground wheels by means of clutches on the ends of the rotator shaft. In my device I provide a sprocket 42 on the right hand end of shaft I2 and drive the rotator from this sprocket by means of a suitable chain. This driving means associated with the rotator is too well known to require illustration and description.

Referring now to Figure 3; I provide a shield 43 for the forward end of belt 26 and pulley ll, this shield being secured preferably to the engine bed by means of brackets 44-44. I provide a shield 45 for the rear end of belt 26 and pulley and secure this shield to post 20 by means of a bracket 46.

It will be seen that the belt will at all times be in view of the operator and that shields 43 and 45 can be easily removed for changing a belt and that practically the only part of the transmission which is subject to wear is the belt, which is inexpensive and easily replaced. Clearly applicants transmission may be used other than on power driven lawn mowers and many minor de tailed changes may be made in the design without departing from the spirit and scope of the invention as recited in th appended claims.

Having thus shown and described my invention I claim:

1. A transmission of the character described, comprising closely spaced driver and driven V belt pulleys and an endless belt therefor, said driven pulley having a shaft rotatably mounted on a pivoted frame, whereby the shaft may be moved for tightening and loosening the belt, an eccentrically mounted member having thereon a rotatably mounted sleeve positioned in front of said shaft, a lever member rotatably mounted near its upper end concentric with said shaft the upper end of which is cam shaped, manual means for operating said cam, whereby when the lower end of the lever is moved rearwardly the cam will engage the roller and push the shaft rearwardly and hold the shaft in its operating position.

2. A device as recited in claim 1; said frame comprising a tube into which said shaft is rotatably mounted and having secured to its ends depending arms, stationary brackets to which the lower ends of said depending arms are pivoted, whereby the shaft may oscillate forwardly and rearwardly on said pivots, means secured at its forward end to the lower end of said lever and extending rearwardly and upwardly to thereby provide remote manual control over the position of said first shaft.

3. A transmission of the character described, comprising a base plate, a driving shaft rotatably mounted on said base plate and having a V belt driving pulley, a driven shaft rotatably mounted in a tube and having a V belt driven pulley secured thereto in alignment with said driving pulley, said tube having rigidly secured thereto depending arms which are pivotally mounted at their lower ends to said base plate, a V belt operatively engaging said pulleys, a depending control lever rotatably mounted on said tube adjacent the driven pulley, the lower end of said control lever having secured thereto means for manual remote control, a bracket secured to the engine mounting of the driven shaft and near the driven shaft, a stud having an eccentrically positioned pintle extending through said bracket and means on said pintle for holding the stud on the bracket in its adjusted position, a sleeve rotatably mounted on said stud, the upper end of said depending lever adapted to act as a cam and rest on said sleeve, whereby when the lower end of the control lever is in its forward position said belt will be loose and when its lower end is moved rearwardly the cam will act on said sleeve to tighten the belt and whereby the tautness of the belt may be adjusted by turning said stud on its pintle.

4. A device as recited in claim 3; said cam having a slight depression into which said sleeve will rest when the control lever is moved to an operating position and means on said cam adapted to limit the movement of the control lever after the sleeve enters the depression.

J. A. EDWIN CARLSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 973,426 Harley Oct. 18, 1910 1,708,903 Schroder Apr. 9, 1929 1,913,040 Pierson June 6,1933 2,047,362 Dunford July 14, 1936 

